Thayer
An old English surname probably meaning “of the people’s army,” though some writers also connected it with the name Theodoric.
The #2,186 most common surname in the United States (2010 Census) — about 1 in every 18,571 Americans shares it.
Etymology
The strongest historical explanation treats Thayer as a form related to an old Germanic compound built from words meaning “people” and “army.” In that analysis, the first element comes from the same root seen in Old English and related languages for “people,” while the second element is the word for “army,” giving a sense like “people’s army” or “folk-army.” Some 19th-century writers also linked it to the personal name Theodoric, via Old French diminutive forms such as Thierry, but they were not fully confident about that connection.
History
The name is long established in English-language records, and American usage became especially visible in the 19th century. Historical surname writers disagreed a little on whether Thayer developed directly from a Germanic compound or through French forms of Theodoric, so the surname is best treated as having a Germanic origin with some uncertainty in the exact pathway. In the United States it became familiar enough to appear regularly in directories and census-style lists.
Origin
Regions
Variant spellings
Fun fact
One early scholar grouped Thayer with other ancient Germanic names built from elements meaning “people” and “army,” which was a common way to form noble or martial personal names.
From the historical record
“THAXTER, V. Thackster. THAYER (A.-Fr.-Teut.)represents an O.Frank, cognate, 'Ihiadher (A.D. ,799), of A.-Sax. rAeorfAere= National A.Kyci\thiad- = O.E. l>e<f<i=O.Sax. thiod = Goth. J)/«rfa = O.N. \i6S (O.H.Ger. diot{a), nation, people + her^i (as in O.Sax. and O.H.Ger.) = O.E. here = Goth, harji-s = O.N. herr…”
— Surnames of the United Kingdom: a concise etymological dictionary (2 vols in 1)